Shed-forming mechanism, weaving loom of jacquard type and method for adjusting the number or type of warp yarns of such a loom

ABSTRACT

In a shed-forming mechanism for weaving loom of Jacquard type in which the position of certain warp yarns of the loom is controlled by means which are themselves controlled by a Jacquard system, there are provided, for at least one warp yarn, means for temporarily connecting this yarn on its position control means. The number or the type of warp yarns to be used is adjusted by cutting a warp yarn and by temporarily connecting it with its position control means, such as a heddle or the harness cord associated therewith.

FIELD OF THE INVENTION

[0001] The present invention relates to a shed-forming mechanism and toa weaving loom of Jacquard type equipped with such a mechanism. Theinvention also relates to a method for adjusting the number or type ofwarp yarns of such a loom to be used for a sequence of weaving.

BACKGROUND OF THE INVENTION

[0002] In the domain of weaving looms of Jacquard type used formanufacturing carpets, it is known to use certain warp yarns toconstitute the piles of a carpet, these warp yarns being delivered bythe creel in which are supported reels whose number is equal to that ofthe piles. These warp yarns are unwound from these reels under theeffect of traction thereof.

[0003] Such a weaving loom is generally equipped with a creel comprisingyarns of different colours or types, and, as a function of the sequencesof weaving envisaged, particularly as a function of the patterns of acarpet to be manufactured, the number of these colours or the type ofthese warp yarns may evolve. For example, from a creel provided withreels of warp yarns of ten different colours, it is sometimes opportuneto weave with only eight colours of warp yarns. In that case, it wouldsuit to be able to neutralize two colours of warp yarns for a futuresequence of weaving.

[0004] Two known approaches are sometimes employed for such aneutralization.

[0005] The unnecessary yarns may be removed from the warp and rewound inthe creel. When these warp yarns are to be used again, they must bereintroduced in the loom up to the beating point. Such an operation islong, tedious and, in practice, expensive. It is sometimes necessary toimmobilize a weaving loom for up to three weeks in order to reintroducethese warp yarns.

[0006] The second known approach is more rapid to implement. Itconsists, by a modification of the weave obtained thanks to the Jacquardsystem, in incorporating the unnecessary warp yarns in the background ofthe carpet, arranging for them not to be visible. In that case, theunnecessary yarns correspond to a loss or waste of warp yarns which,when ten colours are reduced to eight, may represent more than 20% byweight of the warp yarns.

[0007] Similar problems may occur with Jacquard weaving looms used forweaving products other than carpets.

[0008] It is a more particular object of the present invention toovercome these drawbacks by proposing a shed forming mechanism whichmakes it possible to neutralize certain warp yarns of a weaving loomsimply, reliably and economically.

SUMMARY OF THE INVENTION

[0009] To that end, the present invention relates to a shed formingmechanism for a weaving loom of the Jacquard type, in which the positionof certain warp yarns of the loom is controlled by means which arethemselves controlled by a Jacquard system, characterized in that, forat least one warp yarn, means are provided for temporarily connectingthis yarn on the afore-mentioned means for controlling its position.

[0010] Thanks to the invention, the warp yarn may be neutralized byimmobilizing it on its control means which may be a heddle or a harnesscord associated therewith, which makes it possible not to incorporatethis warp yarn in the product being woven, but without having to removeit from the loom. This avoids the subsequent steps of reintroduction ofthe yarn in the loom when it is to be used again for a future sequenceof weaving. In practice, temporary connection means are provided foreach warp yarn of a particular sub-group of warp yarns, for example forall those of a colour likely not to be used for certain patterns.

[0011] According to advantageous aspects of the invention, a shedforming mechanism may incorporate one or more of the followingcharacteristics, taken in all technically possible combinations:

[0012] The temporary connection means are provided on a heddlepresenting an eye for passage of the afore-mentioned warp yarn. In thatcase, they may be provided to comprise a zone of jamming of the yarnmade on a branch of this heddle which extends from its eye. This jammingzone may be formed by a slit made in the afore-mentioned branch.

[0013] The temporary connection means are provided on a harness cord forcontrolling the displacement of a heddle presenting an eye for passageof the warp yarn mentioned above.

[0014] The temporary connection means comprise a sleeve threaded on thebranch of the heddle or on the harness cord, mobile in its longitudinaldirection and adapted to cover the jamming zone and that part of theyarn jammed therein.

[0015] An element is provided for keeping said warp yarn temporarilyconnected on its control means in a position disengaged from the shed.

[0016] The invention also relates to a weaving loom of Jacquard type,particularly a weaving loom intended for manufacturing carpets, equippedwith a shed forming mechanism as described hereinabove. Such a loom iseasier and more economical to operate than those of the state of theart.

[0017] Finally, the invention relates to a method for adjusting thenumber or type of warp yarns of a weaving loom of Jacquard type to beused for a given sequence of weaving, in which, when it is desired toneutralize a warp yarn for the following picks, the following steps arecarried out, in which:

[0018] a) the warp yarn is cut between a heddle of which it traverse aneye and the beating point and

[0019] b) the cut end of that part of the yarn still engaged in the eyeis temporarily connected on the heddle or on a harness cord forcontrolling the displacement of this heddle.

[0020] Thanks to this method, the neutralization of a warp yarm or of aseries of warp yarns when articles to be woven are changed, may beeffected rapidly, without involving long and tedious manoeuvres when thewarp yarns or yarns must be used again in a subsequent sequence ofweaving.

[0021] According to advantageous but non-obligatory aspects of theinvention, this method may incorporate one or more of the followingcharacteristics:

[0022] an additional step is provided in which the heddle is displacedtowards an upper or lower position where it is maintained during thesequence of weaving in question.

[0023] an additional step is provided in which the yarn temporarilyconnected to its control means is kept in a position disengaged from theshed.

[0024] during step a), the yarn is cut between the reed of the loom andthe beating point and, between steps a) and b), a step is provided inwhich the end of the yarn is withdrawn from the reed.

[0025] Finally, the invention relates to a method for adjusting thenumber or type of warp yarns of a weaving loom of Jacquard type to beused for a sequence of weaving in which, when it is desired to use forthe following picks a warp yarn previously neutralized by a method suchas described hereinabove, steps are carried out, in which:

[0026] f) the afore-mentioned end of the warp yarn is disconnected fromthe heddle or harness cord mentioned above,

[0027] g) this end is passed in the reed again, and

[0028] h) this end is joined to the fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be more readily understood on reading thefollowing description of two forms of embodiment of a weaving loom andof a shed forming mechanism associated therewith in accordance with theinvention, and of a method according to the invention, given solely byway of example with reference to the accompanying drawings, in which:

[0030]FIG. 1 schematically shows a weaving loom according to theinvention.

[0031]FIG. 2 is a view on a larger scale of detail II in FIG. 1.

[0032]FIG. 3 is a view similar to FIG. 2 when a warp yarn is beingneutralized.

[0033]FIG. 4 is a view similar to FIG. 2 when the warp yarn has beenneutralized.

[0034]FIG. 5 is a view on a larger scale of a part of a heddle and of aharness cord of the loom of FIGS. 1 to 4.

[0035]FIG. 6 is a view similar to FIG. 5 for a mechanism in accordancewith a second form of embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Referring now to the drawings, the weaving loom M shown in theFigures is supplied with warp yarns 10 by a creel 12 in which are storedreels 14 from which the warp yarns 10 are unwound.

[0037] In order to render the drawings clearer, only four warp yarns 10have been shown, it being understood that the number of warp yarns ofsuch a loom may be several thousands, as a function of the size of theproduct to be woven.

[0038] In the embodiment shown, the loom M is used for weaving carpetsT₁ and T₂ which, after having been woven, are separated from each otherby means of a cutter 16 which cuts their piles P₁ and P₂.

[0039] The loom M is equipped with heddle frames (not shown), of whichthe vertical oscillation movement is controlled by a dobby or a cammechanism, (likewise not shown). These frames serve to weave thebackground fabric of the carpets T₁ and T₂.

[0040] The loom M comprises a reed or sley 18 intended to regularly beatthe manufactured fabric at the level of a beating point 20, after eachpick has been introduced in the shed F in a direction substantiallyperpendicular to that of the warp yarns 10.

[0041] In order to weave the carpets T₁ and T₂, each warp yarn 10intended to form the piles is controlled individually, in its verticaloscillation movement F₁, by a heddle 22 provided with an eye 24 forpassage of the warp yarn 10 in question. In order to render the drawingclearer, only four heddles 22 have been shown. Each heddle is fastenedby its upper end 22 a to the lower end 26 a of a harness cord 26, theassembly of the harness cords 26 constituting the harness H of the loomM. The vertical displacement of the harness cords 26 is controlled, inmanner known per se, by a Jacquard system 30.

[0042] When a warp yarn 10 is to be neutralized, i.e. no longerincorporated in one of the carpets T₁ or T₂ to be woven, this yarn 10 iscut in a zone Z₁ included between the reed 18 and the beating point 10,as represented by a cross in FIG. 2. The end 10 a of the part 10 b ofthe yarn 10 which remains engaged in the eye 24 of the correspondingheddle 22 is then bent towards this heddle, as represented by arrow F₂in FIG. 3.

[0043] This end 10 a is then temporarily immobilized on the heddle 22 byintroducing it in a slit 22 b made in an upper branch 22 c of the heddle22, this branch 22 c connecting the eye 24 to the upper end 22 a of theheddle 22. The introduction of the end 10 a in the slit 22 b isrepresented by arrow F₃ in FIG. 5.

[0044] Once the end 10 a is engaged in the slit 22 b, a sleeve 32 ofplastics material is slid along the branch 22 c, as represented by arrowF₄, so that this sleeve covers the slit 22 b, to such an extent that theend 10 a is immobilized on the heddle 22 by jamming.

[0045] The sleeve 32 remains in position at the level of the slit 22, asthe total transverse section of the heddle is slightly greater at thatlevel than in the other parts of the branch 22 c.

[0046] The sleeve 32 is to be distinguished from the sheath 34 which isengaged and possibly retracted around the ends 22 a and 26 a, in orderto guarantee the fastening of the heddle 22 on the harness cord 26.

[0047] The sleeve 32 may, by default, be positioned at the level of theslit 22 b, in which case it is displaced, in the direction opposite thatof arrow F₄, in order to clear access to the slit before introduction ofthe end 10 a, as represented by arrow F′₄ in FIG. 3.

[0048] When the upstream part of the yarn 10, still engaged in the eye24, has been immobilized on the heddle 22, the system 30 is controlled,in particular by computer programmation, so that the heddle 22 isbrought near the position of top dead centre of its path, and eventhereabove, as represented by arrow F₅ in FIG. 4. The unused yarn 10 maybe disengaged from the shed thanks to a cross-beam 38 disposed in thedirection of the weft yarns between this yarn 10 and the used yarns,this cross-beam supporting this yarn above the shed. In this way, duringthe weaving sequence to come, the immobilized yarn 10 does not undergoefforts of friction by the other warp yarns which move both in thedirection of the double arrow F₁ and in a direction of advance towardsthe beating point 20.

[0049] In a variant, it is possible to provide that the zone of cut Z₁be located between the reed 18 and the heddles 22. In that case, part 10c of the cut yarn 10 is withdrawn from the reed 18 before the sequenceof weaving to come is started.

[0050] When it is desired to re-use a previously neutralized yarn 10,the sleeve 32 is slid in order to access the slit 22 b and to remove theend 10 a of the yarn 10 in question therefrom. The end 10 a is thenintroduced between the corresponding teeth of the reed 18 and this endis joined to the fabric previously manufactured.

[0051] The programmation of the system 30 is then modified so that theheddle 22 and the harness cord 26 are animated by a vertical oscillatingmovement F₁ corresponding to the desired weave.

[0052] Weaving can then be proceeded with, using the yarn 10 inquestion.

[0053] According to a first variant of the invention (not shown), themeans for temporarily connecting the end of the harness cord yarn on theheddle may be provided at the level of its lower branch 22 d, i.e.between the eye 24 and its lower end 22 e fast with a return spring 36.In that case, when the corresponding yarn 10 has been connected with theheddle, the latter is displaced to near the bottom dead centre of itspath, in order to disengage the yarn from the shed. In that case, across-beam equivalent to the cross-beam 38 is advantageously arrangedbelow the shed in order to keep the yarn 10 at a distance therefrom.

[0054] In the second form of embodiment of the invention shown in FIG.6, elements similar to those of the first embodiment bear identicalreferences increased by 100.

[0055] This embodiment differs from the preceding one in that the meansfor temporarily connecting the free end 110 a of the part 110 b of awarp yarn 110 engaged in the eye 124 of a heddle 122 are provided, noton the heddle itself, but at the level of the harness cord 126associated therewith, in the form of a loop 126 b in which is engagedthe end 110 a which is advantageously knotted at that level.

[0056] According to an optional aspect of the invention shown in dashedand dotted lines, a sleeve 132 of the type of sleeve 32 of the firstembodiment, may also be used for covering the opening 126 b and the end110 a which, in that case, is not necessarily knotted.

[0057] Other forms of embodiment of means for temporarily connecting theend of a warp yarn on its position control means, in its verticaloscillation movement F₁, may be envisaged within the framework of thepresent invention.

What is claimed is:
 1. A shed forming mechanism for a weaving loom ofthe Jacquard type, in which the position of certain warp yarns of theloom is controlled by means which are themselves controlled by aJacquard system, wherein, for at least one warp yarn, means are providedfor temporarily connecting said yarn on said means for controlling itsposition.
 2. The mechanism of claim 1, wherein said temporary connectionmeans are provided on a heddle presenting an eye for passage of saidwarp yarn.
 3. The mechanism of claim 2, wherein said temporaryconnection means comprise a zone of jamming of said yarn made on abranch of said heddle extending from said eye.
 4. The mechanism of claim3, wherein said jamming zone is formed by a slit made in said branch. 5.The mechanism of claim 4, wherein said temporary connection meanscomprise a sleeve threaded on said branch, mobile in its longitudinaldirection and adapted to cover the jamming zone and that part of theyarn jammed therein.
 6. The mechanism of claim 1, wherein said temporaryconnection means are provided on a harness cord for controlling thedisplacement of a heddle presenting an eye for passage of said warpyarn.
 7. The mechanism of claim 6, wherein said temporary connectionmeans comprise a sleeve threaded on said harness cord, mobile in itslongitudinal direction and adapted to cover the jamming zone and thatpart of the yarn jammed therein.
 8. The mechanism of claim 1, wherein itcomprises an element for keeping said warp yarn temporarily connected onits control means in a position disengaged from the shed.
 9. A weavingloom of Jacquard type, particularly a weaving loom intended formanufacturing carpets, equipped with the shed forming mechanism ofclaim
 1. 10. A method for adjusting the number or type of warp yarns ofa weaving loom of Jacquard type to be used for a given sequence ofweaving, in which, when it is desired to neutralize a warp yarn for thefollowing picks, it consists in the following steps of: a) cutting saidwarp yarn between a heddle of which it traverse an eye and the beatingpoint, b) temporarily connecting the cut end of that part of the yarnstill engaged in said eye, on said heddle or on a harness cord forcontrolling the displacement of said heddle.
 11. The method of claim 10,wherein it comprises an additional step of: c) displacing said heddletowards an upper or lower position where it is maintained during saidsequence of weaving.
 12. The method of claim 10, wherein it comprises anadditional step of: d) keeping said yarn temporarily connected to itscontrol means in a position disengaged from the shed.
 13. The method ofclaim 10, wherein, during step a), said yarn is cut between the reed ofthe loom and the beating point and, between steps a) and b), a step isprovided in which: e) said end of said yarn is withdrawn from said reed.14. Method for adjusting the number or type of warp yarns of a weavingloom of Jacquard type to be used for a sequence of weaving in which,when it is desired to use for the following picks a warp yarn previouslyneutralized by the method of claim 10, steps are carried out, in which:f) said end of said warp yarn is disconnected from said heddle or saidharness cord, g) said end is passed in said reed again, and h) said endis joined to the fabric.